Milk is naturally white and most cheese making (except blue cheese) does not significantly change the colour and thus without colourants most cheese would be white. Many colourants can be used in making cheese, there is a separate general article on Wiki: Colourants. This article is specifically about Annatto, the most common colourant added to milk in cheese making for it’s common yellow > orange > red colour.
Historically, yellow cow’s milk cheese was thought to be higher quality and thus more desirable as it was made from milk rich in butterfat. However, the yellow colour is actually from the amount of carotenes in the butterfat, and secondarily from the globule size of the butterfat in the milk. Carotene is a pigment from green foods such as grass and is more noticeable when cow’s feed changes from winter to pasture in the spring. The amount of carotene is also a function of the type of cow. Goat’s and ewe’s / sheep’s milk contain no carotene and thus their cheeses are normally white. To cater to public demand for the yellower cheeses and to be cost effective, cheese makers started adding colourants or dyes to cheese rather than have using high carotene butterfat’s. This evolved to the modern popular cream coloured Gouda, orange coloured Cheddar, and reddish coloured Leicester cheeses historically through the addition of a colourant called Annatto.
Annatto is by far the most common colourant in cheese as it imparts minimal flavour, is reasonably benign to the cheese making process, and depending on dosage amount, will impart a cream to orange to deep red colour. Annatto is made from the seed of the Achiote tree, native to tropical America, and while it can be purchased in it’s raw seed format, most Annatto for cheese making is sold in aqueous form with varying concentration. Note, Annatto is also available in an oil soluble form where it is used for cooking such as in some Latin American dishes. This form of Annatto is not used in cheese making as it imparts flavour.
Amount To Add
When added to milk, Annatto imparts little colour change, this is because it generally attaches to the fat in the milk, and effectively hides. However, the colour becomes darker due to three effects:
- Removal of whey either through draining or expulsion in rennet coagulated cheeses.
- As the cheese ages it becomes more acidic as the remaining lactose is consumed by the lactic bacteria (starter culture), this results in a darker colour, somewhat similar to how a phenopthalien dye in acid test kits (popular in swimming pool test kits) changes color depending on how basic/acidic the solution is.
- If used in an open rind cheese, as it ages the cheese will dehydrate, resulting in a smaller cheese and more concentrated dye.
Therefore do not over-dose even though there is minimal initial colour change in milk. For illustration, see two pictures to right of cut curds with Annatto and resultant Gouda cheese at brining stage. Common dosage rates guidelines for Annatto are:
- 1 drop per liter / 3 drops per 1 US gallon milk for Gouda
- 2-3 drops per liter / 8-12 drops per 1 US gallon milk for Cheddar
- 4 drops per liter / 16 drops per 1 US gallon milk for Red Leicester
- Annatto solutions are not standardized, your product’s strength may easily vary.
- Some CFO members have reported needing lower rates when using store bought pasteurized milk.
- Colour is subjective, a cream coloured Gouda may appear white to one person and yellow to another.
- Adjust dosage rate up or down depending on your results.
Annatto seeds in grocery stores, aqueous form from Cheese Making Supply Stores.
Standard room temperature as Annatto is quite inert.